Mechanical impact delay and firing device for fuze applications



Dec. 5, 1961 3,011,442

H. G. WENIG MECHANICAL IMPACT DELAY AND FIRING DEVICE FOR FUZE APPLICATIONS Filed Sept. 2, 1960 INVENTOR.

l-LBW ni BY B 5 3,011,442 MECHANICAL IMPACT DELAY AND FIRING DEVICE FOR FUZE APPLICATIONS Harold G. Wenig, Brooklyn, N.Y., assignor to the United States of America as represented by the Secretary of the Army Filed Sept. 2, 1960, Ser. No. 53,858 1 tilaim. (Cl. 102-75) This invention relates to a mechanical impact fuze and more particularly to a base detonating fuze for spin stabilized projectiles having a mechanical delay.

Briefly, my invention comprises a fuze having a detonator and booster which is adapted to be connected to the end of a spin stabilized projectile. The fuze carries a plate which is provided with a spiral groove and a primer located at the outward end of the groove. A ball is held in fixed position in the fuze and released into the groove upon impact at which time it moves outwardly under the influence of centrifugal force to strike the primer to cause detonation. The length of time required for the ball to traverse the spiral groove provides a time delay between impact and detonation.

An object of this invention is to provide an impact type fuze having a mechanical time delay after impact.

Another object of this invention is to provide a fuze having no stored energy so as to be safe when being handled.

A further object is to provide a fuze having a ball carried by an inertia member and releasable upon impact to move outwardly by centrifugal action to cause detonation.

Still another object is to provide a fuze which is safe for handling and is very simple in construction and cheap to manufacture.

These and other objects will become more apparent when reference is bad to the following detailed description and drawing in which:

FIGURE 1 is an axial sectional view of the fuze taken on the line 11 of FIGURE 2 and showing the parts in their safe position,

FIGURE 2 is a cross-sectional view taken on the line 2-2 of FIGURE 1 and looking in the direction of the arrows, and

FIGURE 3 is a sectional view taken on the line 33 of FIGURE 1 looking in the direction of the arrows.

Referring to the drawing the fuze is provided with the body 1 having pilot or reduced portion 2 with external threads 3 for reception in a spin stabilized projectile. Received within and threadedly connected to the reduced portion 2 of the housing is the booster cup 4 carrying booster charge 5. The housing is bored as indicated at 6 and this bore is provided with the annular groove 7. A disk 8 is received in the bore 6 and is held against rotation with respect to the housing by the key 9. The disk is provided with a central square through passageway 10 for a purpose to be described. The disk is also provided with the spiral groove 11 which communicates with the central passageway 10 and has disposed in the outer end thereof the primer 12. The disk is further provided with an axial passage 13 which communicates with groove 11 and carries the detonator 14.

Abutting the disk 8 is a second disk which is received and keyed in the bore 6 of the housing 1 and held therein by means of a snap ring 16 received in the housing groove tates atent the nose cap is provided with the block 19' having the.

central seat 20.

Slidably received in the aligned passageways 10 and 17 of the disks is the square shaft 21 which is provided with the head 22 and this head is received in the seat 21) of the block 19. The compression spring 23 surrounds the shaft 21 and reacts between the disk 15 and head 22 to urge the shaft rearwardly. The shaft 21 is provided with the recess 24 which carries the ball 25.

In operation the projectile and fuze are travelling in flight as viewed in FIGURE 1, the parts are in theposition shown and the projectile and fuze are spinning about the axis of flight. When the projectile strikes the target the inertia of the shaft 21 causes it to move inwardly against the action of the spring 23 until the recess 24 in the shaft aligns with the groove 11 in disk 8. At this time the ball moves radially outwardly due to centrifugal force into the groove 11 and continues to travel in the groove until it strikes primer 12. At this time the primer ignites and detonation occurs. It can be seen that delay will occur between impact and detonation due to the time required for the ball to travel the length of the groove. This time may be varied from a minimum in which case the groove 11 would be straight and radial to a considerable delay in which case the groove could have a complete or several complete convolutions.

It will be noted that my fuze has no storedenergy to initiate the primer, all of the energy being obtained from the spinning of the projectile. Even if the projectile were given a severe enough jolt in handling to move the shaft forwardly enough to release the ball into groove 11 the ball would not initiate the primer.

It should be'noted that in lieu of the primer 12 another type device to be actuated could be substituted. This device could take the form of a piezo-electn'c crystal, an electric switch, a spring to be compressed or the like.

Thus, it will be seen that I have provided a fuze for a projectile that is entirely safe to handle, is very simple and cheap to manufacture and is reliable for use in a spin stabilized projectile.

I claim:

A centrifugally actuated fuze for spin-stabilized projectile, said fuze comprising a body having a reduced externally threaded portion for the attachment of said fuze in the fuze well of the spin stabilized projectile;

a booster charge in said reduced portion, there being an axial bore in said body and a nose cap carried by said body, a block having a central seat in its inner face secured to the frontal wall of said nose cap, a first disc 'having an axially disposed square bore therethrough secured in said axial bore in said body, said first disc having a spiral groove in the outer face thereof, said groove radiating outwardly and communicating at its inner end with said square bore in said first disc, a detonator disposed adjacent the outer end of said groove, there being a second bore in said first disc and spaced from said square bore, said second bore communicating with the outer end of said groove in said first disc, a primer housed in said second bore, a second disc secured in said body and arranged in abutting relation with said first disc, there being an axially disposed square bore through said second disc,

a shaft having a square cross section slidable in said square bores in said first and second discs, said shaft having a radial recess near its inner end and an integral head at its outer end, said head normally received in said central seat in said block on said nose cap, a ball normally housed in said recess and restrained by said first disc and a spring normally biasing between the outer face of said second disc and said head on said shaft, said shaft moving inwardly upon projectile impact to align said ball with the inner end of said spiral groove in said first disc to release said ball from the recess in said shaft into said spiral groove under influence of centrifugal force of projectile spin and strike said detonator.

References Cited in the file of this patent UNITED STATES PATENTS 988,846 Abendroth Apr. 4, 1911 1,890,176 Brandt Dec. 6, 1932 1,999,747 Aragone Apr. 30, 1935 2,304,106 Lake Dec. 8, 1942 2,837,999 Lindsay June 10, 1958 

